Well known techniques exist for preparation of cement-based self-leveling compositions containing mineral aggregates, organic additives, one being a plasticizer, and water. The great advantage of self-leveling compositions normally lies in the ease and rapidity of use, since leveling of such compositions with a straightedge or equivalent means is facilitated or unnecessary.
Thus, there are known:
cement-based self-leveling compositions containing, as plasticizer, for example, a formaldehyde melamine, a melamine derivative or a sulfonated naphthalene. In general, however, because their fluidity exists only for a limited time, such compositions must be placed on the site rapidly after preparation thereof (see, for example, German Utility Model DE 29518306). Methods exist for maintaining the fluidity of such compositions during time, either by adding the plasticizer at timed intervals or by incorporating more plasticizer or by increasing the quantity of mixing water, but for economic and/or technical reasons they are not satisfactory; PA1 cement-based self-leveling compositions containing a special plasticizer which makes it possible to maintain fluidity over time. This may be a plasticizer based on carboxylated vinyl monomers: see, for example, European Patent Applications No. 0725044 and 0753489, wherein the fluidity is maintained for at least 6 hours. The main disadvantage of the compositions described in these two patent applications is one of long setting times. This makes it difficult or even impossible on the following day for persons to walk on toppings manufactured with these compositions for the purpose, for example, of finishing tasks. PA1 lignosulfonates; PA1 plasticizers of the polynaphthalenesulfonate type; PA1 plasticizers of the polymelaminesulfonate type; PA1 plasticizers based on carboxylated vinyl monomers and possibly on sulfonated vinyl monomers. PA1 1) the composition can be prepared in a standard central concrete depot, without modification of such concrete depot, and be delivered ready for use on the site by transit mixers. If necessary, the fluidity of the composition is adjusted by supplementary addition of plasticizer and/or water on the site. In this way homogeneity of the mix is favored; PA1 2) the fluidity of the composition eliminates the traditional operations of spreading, vibrating, leveling with a straightedge or equivalent means, as well as the operation of floating, provided the normal conditions of use are respected by the person skilled in the art. To obtain a flat and smooth surface, it is sufficient to pass a finishing bar and/or a broom over the surface of the fresh product. In addition, the maintenance of this fluidity for a period of time sufficient to place the material (on the order of 2 to 4 hours) and the good kinetics of setting and hardening of the composition permit access of persons on the topping on the day following placement of the composition; PA1 3) the composition, with which a topping can be rapidly completed, makes it possible to achieve great daily productivity, of at least 800 m.sup.2 per day, with a crew of two or three topping workers. PA1 R is a hydrogen atom or a monovalent hydrocarbon group, which may or may not be saturated, containing from 1 to 18 (inclusive) carbon atoms and possibly one or more hetero atoms: preferably R is a hydrogen atom or a monovalent hydrocarbon group, which may or may not be saturated, containing from 1 to 4 carbon atoms; PA1 50% to 100% of the Ri are ethylene, 0 to 50% of the Ri are propylene and 0 to 5% of any other Ri are similar to or different from each other and represent an alkylene such as butylene, amylene, octylene or cyclohexene, or an arylene such as styrene or methylstyrene; these Ri may or may not include one or more hetero atoms; PA1 Q is a hydrocarbon group containing from 2 to 18 (inclusive) carbon atoms and possibly one or more hetero atoms; preferably Q is a hydrocarbon group containing from 2 to 12 (inclusive) carbon atoms, more preferably from 2 to 6 (inclusive) carbon atoms, and even better it represents ethylene or propylene; PA1 A is an alkylidene group containing from 1 to 3 (inclusive) carbon atoms: preferably A represents the methylene group; PA1 the Rj are similar to or different from each other and can be chosen from among: PA1 "n" is an integral number between 20 and 250, terminal groups included; PA1 "r" is the number of [R--O(Ri--O)n] groups carried by the assembly of the Rj, PA1 "q" is the number of [R--O(Ri--O)n] groups carried by Q, PA1 the sum "r+q" is at most equal to 3; PA1 "y" is an integral number equal to 1 or 2. PA1 1--at least 50% of the Ri are ethylene and any other R.sub.i are propylene; PA1 2--R.sub.j is chosen from among the --CH.sub.2 --PO.sub.3 H.sub.2, --C.sub.2 H.sub.4 N(CH.sub.2 --PO.sub.3 H.sub.2).sub.2 and --C.sub.3 H.sub.6 N(CH.sub.2 --PO.sub.3 H.sub.2).sub.2 groups, which may or may not be in salt form; PA1 3--"n" is between 30 and 150 (terminal groups included), and even better between 50 and 100 (terminal groups included); PA1 4--"r+q" is equal to 1; PA1 5--"y" is equal to 1. PA1 water; PA1 at least one anti-foaming agent which is non-water-soluble or scarcely water-soluble; PA1 at least one plasticizer (I) of formula (I) and if appropriate another plasticizer such as a water-soluble or water-dispersible plasticizer (PCP); PA1 at least one organic compound (O) containing: PA1 at least one mineral stabilizer when the pH of the said premix is higher than 7, such as the clays and the sepiolites; PA1 if appropriate, an acid or a base to adjust the pH of the said premix. PA1 the term "non-water-soluble or scarcely water-soluble anti-foaming agent" means an anti-foaming agent that is scarcely soluble or insoluble in aqueous media at ambient temperature (about 20.degree. C.) and atmospheric pressure; PA1 the term "uniform mix" means a mix which, left to stand, can transform from a clear mix (such as a microemulsion) to a turbid mix (such as an oil-in-water emulsion). Sometimes a fine film, generally of foam, may be present on the surface of the uniform mix. PA1 (a) 200 to 500 kg/m.sup.3 of Portland cement; PA1 (b) 0 to 400 kg/m.sup.3 of fine mineral aggregates; PA1 (c) 900 to 1900 kg/m.sup.3 of sand with maximum grain size smaller than or equal to 10 mm, preferably smaller than or equal to 5 mm; PA1 (d) water, in a water-to-cement ratio (W/C) greater than or equal to 0.4; PA1 (e) at least one anti-foaming agent; PA1 (f) at least one thickening agent; PA1 (g) at least one compound (I) as plasticizer, in a proportion of 0.2 to 2% by dry weight relative to the weight of cement, and possibly at least one plasticizer (PCP). PA1 (a) 200 to 400 kg/m.sup.3 of Portland cement; PA1 (b) 100 to 400 kg/m.sup.3 of fine mineral aggregates; PA1 (c) 1100 to 1600 kg/m.sup.3 of sand with maximum grain size smaller than 10 mm, preferably smaller than or equal to 5 mm; PA1 (d) water, in a water-to-cement ratio (W/C) of between 0.6 and 1.2; PA1 (e) at least one anti-foaming agent; PA1 (f) at least one thickening agent; PA1 (g) at least one compound (I) as plasticizer, in a proportion of 0.2 to 2% by dry weight relative to the weight of cement, and possibly at least one plasticizer (PCP). PA1 preparation of a mix of a self-leveling composition, such as defined in the foregoing description; PA1 transportation if necessary of the said mix in a transit mixer to the site of the floor topping; PA1 preparation of the new or restored topping support in conformity with the engineering codes in force in the country under consideration. In France, for example, these codes can be found in the pertinent unified technical documents (D.T.U.), in particular D.T.U. 26-2, D.T.U. 65-7 and D.T.U. 65-8, and in the technical specifications in force; PA1 if necessary, adjustment of the rheology of the mix by means of a supplementary addition of the plasticizer defined hereinabove, or of water; PA1 pumping and pouring of the said mix onto the support and passage of the finishing bar over the surface.
The plasticizers known heretofore in the field of self-leveling toppings can be generally classified into four major families:
As indicated hereinabove, plasticizers based on carboxylated vinyl monomers are currently preferred, because they lead to maintenance of fluidity over time, although such maintenance of fluidity is often achieved at the expense of short-term strength.